When a block (MB22) of which motion vector is referred to in the direct mode contains a plurality of motion vectors, 2 motion vectors MV23 and MV24, which are used for inter picture prediction of a current picture (P23) to be coded, are determined by scaling a value obtained from averaging the plurality of motion vectors or selecting one of the plurality of the motion vectors.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image coding method for coding a current block included in a current picture, the picture coding method comprising: referring to a first list in which smaller indices are assigned to pictures preceding the current picture in display order than indices assigned to pictures following the current picture, the first list being a list of index associating blocks included in the current picture with each picture that is referred to by the blocks; selecting, from the first list, as a first reference picture, a picture with the smallest index out of a plurality of pictures that are referred to by a plurality of neighboring blocks, the plurality of neighboring blocks being at the neighborhood of the current block in the current picture; referring to a second list in which smaller indices are assigned to pictures following the current picture in display order than indices assigned to pictures preceding the current picture, the second list being a list of index associating blocks included in the current picture with each picture that is referred to by the blocks; selecting, from the second list, as a second reference picture, a picture with the smallest index out of the plurality of pictures; and predictive-coding the current block by referring to the first reference picture and the second reference picture.
2. The image coding method according to claim 1 , further comprising: determining, when the plurality of neighboring blocks have only one motion vector referring to the first reference picture, the only one motion vector as a first motion vector; and determining, when the plurality of neighboring blocks have only one motion vector referring to the second reference picture, the only one motion vector as a second motion vector; and wherein said predictive-coding of the current block is performed by using the first motion vector and the second motion vector.
3. The image coding method according to claim 1 , further comprising: determining, when the plurality of neighboring blocks have a plurality of motion vectors referring to the first reference picture, a first median value of the plurality of motion vectors as a first motion vector; and determining, when the plurality of neighboring blocks have a plurality of motion vectors referring to the second reference picture, a second median value of the plurality of motion vectors as a second motion vector; and wherein said predictive-coding of the current block is performed by using the first motion vector and the second motion vector.
4. An image coding apparatus which codes a current block included in a current picture, the image coding apparatus comprising: a referring unit: operable to refer to a first list in which smaller indices are assigned to pictures preceding a current picture in display order than indices assigned to pictures following a current picture, the first list being a list of index associating blocks included in a current picture with each picture that is referred to by the blocks, and operable to refer to a second list in which smaller indices are assigned to pictures following a current picture in display order than indices assigned to pictures preceding a current picture, the second list being a list of index associating blocks included in a current picture with each picture that is referred to by the blocks; a selecting unit: operable to select, from the first list, as a first reference picture, a picture with the smallest index out of a plurality of pictures that are referred to by a plurality of neighboring blocks, the plurality of neighboring blocks being at the neighborhood of a current block in a current picture, and operable to select, from the second list, as a second reference picture, a picture with the smallest index out of the plurality of pictures; and a coding unit operable to predictive-code the current block by referring to the first reference picture and the second reference picture.
5. The image coding apparatus according to claim 4 , further comprising: a first determining unit operable to determine, when the plurality of neighboring blocks have only one motion vector referring to the first reference picture, the motion vector as a first motion vector; and a second determining unit operable to determine, when the plurality of neighboring blocks have only one motion vector referring to the second reference picture, the motion vector as a second motion vector; and wherein said coding unit is operable to predictive-code the current block by using the first motion vector and the second motion vector.
6. The image coding apparatus according to claim 4 , further comprising: a first determining unit operable to determine, when the plurality of neighboring blocks have a plurality of motion vectors referring to the first reference picture, a first median value of the plurality of motion vectors as a first motion vector; and a second determining unit operable to determine, when the plurality of neighboring blocks have a plurality of motion vectors referring to the second reference picture, a second median value of the plurality of motion vectors as a second motion vector; and wherein said coding unit is operable to predictive-code the current block by using the first motion vector and the second motion vector.
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August 30, 2013
February 24, 2015
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